1. Field of the Invention
The present invention relates to an apparatus and method for testing the integrity of the walls and joints of a plurality of interconnected pipe sections. More particularly, an apparatus, comprising an internal testing device constructed of a plurality of tool sections and designed to permit repetitive use of an essentially identical intermediate section to provide a tool capable of testing any desired number of interconnected pipe sections is disclosed. The device of the present invention simultaneously and independently determines the integrity of joints and pipe sections in a plurality of interconnected pipe sections. The device and method of the present invention is conveniently employed to simultaneously test two or three interconnected pipe sections prior to the lowering of these sections into a borehole.
2. Description of the Background
Pressure testing of tubing and pipe sections and particularly of the joints therebetween prior to placement of the pipe into a borehole is required in order to determine the presence of leaks in the pipe section walls or joints. Such testing may be conducted using an external testing tool or an internal testing tool.
An external testing tool generally comprises a cylindrical apparatus having a diameter substantially greater than that of the pipe to be tested. This tool includes appropriately positioned packers on the inside thereof. An internal tool may be lowered about the pipe section and uppermost joint, or may be formed in multiple parts which may be placed around the pipe and/or joint. Testing is achieved by activating the packers and pressurizing the annular space between the pipe or joint and the testing tool with a testing fluid at a known pressure. Leaks may be easily determined by an observable drop in pressure.
Various internal testing tools have also been employed. These tools generally include a cylindrical body having a diameter substantially less than that of the pipe to be tested and having packers on the exterior thereof. Such an internal testing tool is lowered into the interior of the top pipe section to test the integrity of the top pipe or first joint. Setting of the packers and pressurization of the annular space resulting between the interior of the pipe, the exterior of the tool and the packers provides a pressurized test chamber. Again, leaks are easily detected by an observable decrease in the predetermined pressure.
These known testing methods and apparatus have suffered from the ability to provide test results with respect to only one pipe section or joint at a time. The loading of a long pipe string into a borehole, particularly in deep well operations, is extremely time consuming. It is necessary to be sure that there are no leaks in the joints or in the pipe sections themselves. Accordingly, it is necessary to test each and every joint and pipe section. The above known methods require the testing of each pipe section individually as it is added, and greatly increases the time required to make-up, test and move the string into the borehole. The make-up, testing and loading of the pipe string becomes very costly in deep well operations. Accordingly, it would be desirable to test stands of interconnected pipe simultaneously to decrease the time required for pressure testing the drill string.
The present invention overcomes this major difficulty by providing an apparatus and method capable of testing simultaneously and independently the joints and pipe walls of a plurality of interconnected pipe sections. It is most convenient to test two or three sections of pipe in a single stand. The typical height of the derrick permits the convenient manipulation of two or three sections of interconnected pipe in most operations. The time required for testing pipe sections is typically cut by fifty to sixty-seven percent when employing the method and apparatus of the present invention. These savings in time produce significant savings in cost in drilling operations, and are particularly beneficial in deep drilling operations where the tripping of the drill string may consume many hours.